From bf2841b014ff363cfd93ee49c1df55a5277d3d5c Mon Sep 17 00:00:00 2001
From: Martin Petr <martinpetrnp@gmail.com>
Date: Thu, 20 Nov 2025 16:26:59 +0100
Subject: [PATCH] Add serial driver

---
 scripts/run-kernel.sh                         |  2 +-
 src/os/src/kernel/drivers/etc/serial.ts       | 27 ++++++++++++++++
 src/os/src/kernel/index.ts                    | 31 ++++++++++++++++++-
 .../kernel/modules/drivers/drivers.kmod.ts    | 11 +++++++
 4 files changed, 69 insertions(+), 2 deletions(-)
 create mode 100644 src/os/src/kernel/drivers/etc/serial.ts
 create mode 100644 src/os/src/kernel/modules/drivers/drivers.kmod.ts

diff --git a/scripts/run-kernel.sh b/scripts/run-kernel.sh
index 7f45ffd..35d9c56 100755
--- a/scripts/run-kernel.sh
+++ b/scripts/run-kernel.sh
@@ -1,3 +1,3 @@
 ./scripts/build.sh
 
-qemu-system-i386 -kernel "build/out/kernel"
\ No newline at end of file
+qemu-system-i386 -serial stdio -kernel "build/out/kernel"
\ No newline at end of file
diff --git a/src/os/src/kernel/drivers/etc/serial.ts b/src/os/src/kernel/drivers/etc/serial.ts
new file mode 100644
index 0000000..4ef562d
--- /dev/null
+++ b/src/os/src/kernel/drivers/etc/serial.ts
@@ -0,0 +1,27 @@
+import { portin, portout } from "../../../lib/libts/port";
+
+const SERIAL_PORT_COM1 = 0x3f8;
+
+export function kdriver_etc_serial_init() {
+  portout(SERIAL_PORT_COM1 + 1, 0x00); // Disable all interrupts
+  portout(SERIAL_PORT_COM1 + 3, 0x80); // Enable DLAB
+  portout(SERIAL_PORT_COM1 + 0, 0x03); // 38400 baud
+  portout(SERIAL_PORT_COM1 + 1, 0x00);
+  portout(SERIAL_PORT_COM1 + 3, 0x03); // 8 bits, no parity, one stop bit
+  portout(SERIAL_PORT_COM1 + 2, 0xc7); // Enable FIFO, clear them, with 14-byte threshold
+  portout(SERIAL_PORT_COM1 + 4, 0x0b);
+}
+
+export function kdriver_etc_serial_isTransmitBufferEmpty(): boolean {
+  return (portin(SERIAL_PORT_COM1 + 5) & 0x20) !== 0;
+}
+
+export function kdriver_etc_serial_transmit(byte: number): void {
+  while (!kdriver_etc_serial_isTransmitBufferEmpty()) {}
+
+  portout(SERIAL_PORT_COM1, byte);
+}
+
+export function kdriver_etc_serial_read(): number {
+  return portin(SERIAL_PORT_COM1);
+}
diff --git a/src/os/src/kernel/index.ts b/src/os/src/kernel/index.ts
index fc7dd6a..918d4ee 100644
--- a/src/os/src/kernel/index.ts
+++ b/src/os/src/kernel/index.ts
@@ -1,10 +1,39 @@
+import { charc } from "../lib/libts/byte";
+import { padStart } from "../lib/libts/string";
+import { getDate } from "../lib/sys/date";
+import {
+  kdriver_etc_serial_read,
+  kdriver_etc_serial_transmit,
+} from "./drivers/etc/serial";
+import {
+  kmod_drivers_init,
+  kmod_drivers_register,
+} from "./modules/drivers/drivers.kmod";
 import {
   kmod_graphics_vga_clear,
   kmod_graphics_vga_init,
   kmod_graphics_vga_pushLine,
-} from "./modules/graphics/vga";
+} from "./modules/graphics/graphics.kmod";
 
 export function kmain() {
+  kmod_drivers_init();
+
+  kmod_drivers_register();
+
+  kdriver_etc_serial_transmit(charc("H"));
+  kdriver_etc_serial_transmit(charc("e"));
+  kdriver_etc_serial_transmit(charc("l"));
+  kdriver_etc_serial_transmit(charc("l"));
+  kdriver_etc_serial_transmit(charc("o"));
+
   kmod_graphics_vga_init();
   kmod_graphics_vga_pushLine("[Kernel] Kernel initialized successfully.");
+  kmod_graphics_vga_pushLine("Current date: " + getDate().toDateString());
+
+  while (true) {
+    const d = kdriver_etc_serial_read();
+    kmod_graphics_vga_pushLine(
+      "Serial input: 0x" + padStart(d.toString(16), 2, "0")
+    );
+  }
 }
diff --git a/src/os/src/kernel/modules/drivers/drivers.kmod.ts b/src/os/src/kernel/modules/drivers/drivers.kmod.ts
new file mode 100644
index 0000000..4b18b0e
--- /dev/null
+++ b/src/os/src/kernel/modules/drivers/drivers.kmod.ts
@@ -0,0 +1,11 @@
+import { kdriver_etc_serial_init } from "../../drivers/etc/serial";
+
+const drivers = [kdriver_etc_serial_init];
+
+export function kmod_drivers_init(): void {}
+
+export function kmod_drivers_register(): void {
+  for (let i = 0; i < drivers.length; i++) {
+    drivers[i]!();
+  }
+}